Real-Time Transport Protocol (RTP) is a well known protocol for delivering media information (audio and video) over an IP network. The RTP protocol is described in fall in Schulzrinne et al., “RTP: A Transport Protocol for Real-Time Applications,” STD 64, RFC 3550, July 2003. As broadly indicated in FIG. 1, an RTP packet 100 includes an RTP packet header 102 and an RTP payload 104. The RTP header 102 includes various well-known fields of metadata enumerated in FIG. 1. A device which receives the RTP packet uses the information in the RTP header 102 to govern the processing of the information within the payload 104.
RTP requires a separate so-called payload format for each codec. Well known codecs for processing media information include MPEG-2, H.264/MPEG-4 AVC, MP3, and so forth. The payload format specifies the precise manner in which RTP is used to encapsulate the codec data. In other words, a payload format is essentially a mapping specification, which describes in detail how the video or audio data is arranged inside the RTP packets. Each codec has unique complexities. Thus, the task of developing an RTP payload format for a codec raises a number of unique challenges.
The subject matter set forth herein describes an RTP payload format for the Video Codec 1 (VC-1) video codec. VC-1 has broad applicability, being suitable for low bit rate Internet streaming applications to HDTV broadcast and Digital Cinema applications with nearly lossless coding. More specifically, for instance, VC-1 is widely used for downloading and streaming of movies on the Internet, in the form of Windows Media Video 9 (WMV-9). VC-1 has also been adopted as a mandatory compression format for various high-definition DVD formats.
The VC-1 codec is described in “Proposed SMPTE Standard for Television: VC-1 Compressed Video Bitstream Format and Decoding Process,” The Society of Motion Picture and Television Engineers, White Plains, N.Y., Aug. 23, 2005 (henceforth referred to as simply SMPTE 421M). The SMPTE 421M specification is incorporated by reference herein in its entirety.